US Patent No. 9,563,375

METHOD FOR STORING METADATA OF LOG-STRUCTURED FILE SYSTEM FOR FLASH MEMORY


Patent No. 9,563,375
Issue Date February 07, 2017
Title Method For Storing Metadata Of Log-structured File System For Flash Memory
Inventorship Han Sung Chun, Daejeon (KR)
Assignee ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE, Daejeon (KR)

Claim of US Patent No. 9,563,375

1. A method for storing, by a file system, data in a flash memory, the method comprising:
allocating a block to be stored with information to be written;
creating a segment summary information (SS) record for the allocated block to write the created SS record in a temporary list;
creating a segment usage information (SU) record for a segment where blocks in which the SS record is created are positioned
to write the created SU record in the temporary list;

including at least one of the SS record and the SU record written in the temporary list in a checkpoint record; and
writing the checkpoint record in an allocated position,
wherein including the at least one of the SS record and the SU record written in the temporary list in the checkpoint record
includes:

verifying the size of the temporary list and the size of a prereserved space in the checkpoint record; and
when a usable space in the file system is smaller than the size of the temporary list, removing a part of the file system
that is as large as an amount which cannot be written, that is, an amount which cannot be included in the checkpoint record,
from a fore part to directly reflect the removed part to the SS record and the SU record, and including the residual part
in the checkpoint record.